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nnrrnn sr NT .FFIQQ CUT-OFF VALVE OF STEAM-:ENGINES 'Specification ofi'Letters Patent No. 25,936, dated November 1, 1859.

To all'whom it 'may concern:

Be it known that I, EDWARD R. ARNOLD, of the city and county of Providence, in the State of Rhode Island, have invented cer-.

l with the drawings making a part Vof the same,

is a full, clear, and exact description thereof.

Figure l is a side elevation with the front end drawn in section of the cylinder and steam valves chests of an ordinary horizontal engine, to which is applied the apparatus which I claim as my invention. Fig. 2 is an end view and section of the same. Figs. 3 and 4L are details of parts composing my improvement.

The same letters indicate like parts in all the figures.

In my said invention the valves are opened by a cam or tappet having a curvilinear motion operating upon valve rods having a vertilin-ear motion. When the cam or tappet passes by the rods in opening the valves the valves are closed by their gravity, by weights, or springs connected therewith, or by any other suitable means to enable them to rapidly close their ports. And the said cam or tappet which is mounted upon a shaft is capable of being moved upon the said shaft in a direction at right angles to its line of motion, but is not free to turn upon it; and this part of my invention consists in constructing the several parts so that the points at which the valves close may be varied, while the points at which they open remain the same, by making the tappet and the ends of the valve rods inclined in a direction at right angles to their line of motion, or nearly so, and adjusting them with reference to each other in the direction of their inclination.

The second part of my invention consists in regulating the points of the closing of the valves by combining the regulator with the tappet to adjust its lap upon the valve rods and thereby determine the points at which Jthe valves may be liberated, that they may close their ports by their gravity, by weights, springs, or other equivalent means.

In the accompanying drawing A represents a rock shaft which receives a reciproeating motion through its arm B from the eccentric or some other suitable part of the engine. Upon this shaft is mounted the tappet C, capable of being moved freely on the shaft, in a direction at right angles to its line of motion, but prevented from turning upon it by the spline a.

D D are two valve rods with hinged ends operating slide valves (forwhich any other valves may be substituted) in the steam chests E, E.

F F are standards to determine the position into which the hinged ends of the valve rods shall fall.

G G are weights connected with the rods D D to close the valves after the rods are liberated.

b, Figs. 3 and 4L, are steel faces which are removable and are so arranged that the tappet C shall have a true bearing against the rods D D while opening the valve.

As the arm B moves in the direction of the arrow, the tappet C presses against the end of the valve rod D and opens the valve connected with it, at the same time lifting the weight Gr. As the rod D moves in a straight line and the tappet C moves in the arc of a circle, the tappet in its onward course passes under the rod D. As the rod is now liberated the weight G falls and closes the valve, during which period the hinged end of the rod D mounts up on the tappet C. Before the arm B commences its return stroke the hinged end of the rod D falls into position and is operated upon by the tappet C to open its valve, which is closed at the proper time by its weight G. Again as the arm B commences its return stroke the hinged end of the rod D which we have described as mounting up on the tappet C falls into position on the standard F, and the operation goes on as before described.

It will bev seen by this description that the point at which the valves are liberated is dependant upon the lap which the tappet C has on the rods D D', that is the greater the lap the longer will the valve be keptopen, and vice versa, and that this can be varied by moving the t-appet on the shaft.

H is the regulator, which is here represented as the fly-ball kind, connectedv by means of rod I and bell-crank lever QI' or other suitable devices with the tappet C to adjust its lap upon the valve rods, and thereby determine the points at which the valves may be liberated. When the engine moves at a greater speed than that at which it is set the balls of the regulatorrse and by their connections push out the tappet C from the rods D D thereby decreasing its lap upon them, or When the engine moves too slowly the balls of the regulator fall and pull in the tappet thereby increasing its, lap upon the rods.

I do not limit myself to the construction of the several parts Which compose my invention precisely as described, as it is evident that the form position and arrangements of the several parts may be varied Without changing the principle of my invention. Y

I am aware that a helical cam or sliding sleeve With elevations and depressions on its surface adjusted by the governor, and operated on a shaft driven by the engine,

for the purpose of varying the point of cut-Off, is a very old arrangement. To such a device I lay no claim,

What I claim and desire to secure by Letters Patent is,

l. Making the tappet C, Fig. 4, and the ends of the jointed valve rods, D, D, Fig. 3, inclined in a direction at right angles to their lines of motion and combining and arranging them substantially as herein set forth.

2. The combination of the regulator with a tappet constructed and operated substan tially as described for the purpose specified.

EDWARD R. ARNOLD.

Witnesses:

S. AUG. ARNOLD, BENJ. C. GLADDING. 

